1. Field of the Invention
The present invention relates to a rack mount type storage unit. In particular, the invention relates to a rack mount type storage unit applicable to a rack mount type disk array apparatus.
2. Description of the Prior Art
A rack mount type disk array apparatus is well known. Hard disk drives (HDDs) are held in rows in a frame member of the disk array apparatus. A row of the HDDs is mounted on a corresponding single printed circuit board. The HDDs are kept in an attitude parallel to the bottom plate of the frame member. The HDDs are arranged in a direction perpendicular to the bottom plate of the frame member. When the HDD is replaced with new one, the frame member is pulled out from a rack in the horizontal direction. The printed circuit board is then taken out from the frame member along with the HDD to be replaced. The HDD is pulled off from the printed circuit board. A new HDD is then mounted on the printed circuit board. The printed circuit board is retuned to the frame member.
The aforementioned disk array apparatus only enables removal of a HDD along with a corresponding printed circuit board when the HDD is replaced with new one. The HDD cannot solely be removed from the frame member. The replacement of the HDDs is the troublesome operation. In addition, the disk array apparatus should normally keep operating without any discontinuance. The removal of the printed circuit board in the aforementioned manner causes discontinuance in the operation of the disk array apparatus. If the frame member rotates around a predetermined rotation axis in the disk array apparatus, removal and insertion of a HDD can be facilitated in a disk array apparatus located at a higher level.